TUESDAY, July 27 (HealthDay News) -- Weight-loss surgery, also known as bariatric surgery, in the state of Michigan has a relatively low rate of serious complications, a new study suggests.

The lowest rates of complications are associated with surgeons and hospitals that do the highest number of bariatric surgeries, according to the report published in the July 28 issue of the Journal of the American Medical Association.

Rates of bariatric surgery have risen over the past decade and it is now the second most common abdominal operation in the country. Despite declining death rates for the procedures, some groups remain concerned about the risks of the surgery and uneven levels of quality among hospitals, researchers at the University of Michigan pointed out in a news release from the journal's publisher.

In the new study, Nancy Birkmeyer of the University of Michigan, Ann Arbor, and colleagues analyzed data from 15,275 patients who underwent one of three common bariatric procedures between 2006 and 2009. The operations were performed by 62 surgeons at 25 hospitals in Michigan.

Overall, 7.3 percent of patients experienced one or more complications during surgery, most of which were wound problems and other minor complications. Serious complications were most common after gastric bypass (3.6 percent), sleeve gastrectomy (2.2 percent), and laparoscopic adjustable gastric band (0.9 percent) procedures, the investigators found. Rates of serious complications at hospitals varied from 1.6 percent to 3.5 percent.

Infection was the most common type of surgical site complication (3.2 percent) and occurred most often among patients undergoing gastric bypass (4.4 percent) and sleeve gastrectomy (2.5 percent) procedures, the study authors noted.

"Risk of serious complications was inversely associated with average annual bariatric procedure volume," the researchers wrote in their report."Serious complication rates were about twice as high (4 percent) for low-volume surgeons at low-volume hospitals than for high-volume surgeons at high-volume hospitals (1.9 percent)," they added.

The overall rates of serious complications were similar among patients who had bariatric surgery at centers of excellence (COE) hospitals (2.7 percent) and those who had surgery at non-COE hospitals (2 percent), according to the report.

"In terms of outcome by procedure, the data presented does not show which is safer or more preferable long term. While early serious complications are less with banding, this data does not answer what the long term results are of the various procedures, or the need for other procedures," Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City, commented in a news release about the new report.

"In terms of volume, once again we see the importance of frequency and repetition for the best outcomes," Roslin added.

The researchers wrote that their results might not apply outside of the state of Michigan or to surgeries performed in community settings, but said they represented "useful safety performance benchmarks for hospitals performing bariatric surgery."